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We used Gaia Data Release 2 to search for upcoming photometric microlensing events, identifying two candidates with high amplification. In the case of candidate 1, a spectrum of the lens (l1) confirms it is a usdM3 subdwarf with mass…

Solar and Stellar Astrophysics · Physics 2018-12-12 Peter McGill , Leigh C. Smith , N. Wyn Evans , Vasily Belokurov , Zenghua Zhang

In this work, we use $13$ microlensing candidates with dark lenses from OGLE III catalogue \cite{2016MNRAS.458.3012W} and cross-match them with the GAIA catalogue. We identify the microlensing source stars in the GAIA catalogue by comparing…

Solar and Stellar Astrophysics · Physics 2022-03-10 Amirhosein Dehghani , Sohrab Rahvar

Due to the choice of very dense star fields for a higher event rate, the current microlensing searches suffer from large uncertainties caused by blending effect. To measure light variations of microlensing events free from the effect of…

Astrophysics · Physics 2007-05-23 Cheongho Han

The rapid analysis of ongoing gravitational microlensing events has been integral to the successful detection and characterisation of cool planets orbiting low mass stars in the Galaxy. In this paper we present an implementation of search…

Instrumentation and Methods for Astrophysics · Physics 2015-12-23 Alistair McDougall , Michael D. Albrow

The status of searches for gravitational microlensing events of the stars in our galaxy and in other galaxies of the Local Group, the interpretation of the results, some theory, and prospects for the future are reviewed. The searches have…

Astrophysics · Physics 2011-05-05 Bohdan Paczynski

Astrometric observations of microlensing events were originally proposed to determine the lens proper motion with which the physical parameters of lenses can be better constrained. In this proceeding, we demonstrate that besides this…

Astrophysics · Physics 2007-05-23 Cheongho Han

Scores of on-going microlensing events are now announced yearly by the microlensing discovery teams OGLE, MACHO and EROS. These early warning systems have allowed other international microlensing networks to focus considerable resources on…

Astrophysics · Physics 2007-05-23 Penny D. Sackett

The abundance of dark matter (DM) subhalos orbiting a host galaxy is a generic prediction of the cosmological framework, and is a promising way to constrain the nature of DM. In this paper, we investigate the use of machine learning-based…

Astrophysics of Galaxies · Physics 2023-01-02 Abdullah Bazarov , María Benito , Gert Hütsi , Rain Kipper , Joosep Pata , Sven Põder

We introduce a method to infer the vertical distribution of stars in the Milky Way using a Poisson likelihood function, with a view to applying our method to the Gaia catalogue. We show how to account for the sample selection function and…

Astrophysics of Galaxies · Physics 2021-12-08 Andrew Everall , N. Wyn Evans , Vasily Belokurov , Douglas Boubert , Robert J. J. Grand

We propose a method to remove the mass sheet degeneracy that arises when the mass of galaxy clusters is inferred from gravitational shear. The method utilizes high-redshift standard candles that undergo weak lensing. Natural candidates for…

Astrophysics · Physics 2009-10-30 Tsafrir S. Kolatt , Matthias Bartelmann

The probability of detecting a planetary companion of a lensing star during a microlensing event toward the Galactic center, averaged over all relevant event and galactic parameters, when the planet-star mass ratio $q=0.001$ has a maximum…

Astrophysics · Physics 2009-11-06 S. J. Peale

We investigate constraints on the abundance of primordial black holes (PBHs) as dark matter (DM) candidates using five years of microlensing data from the OGLE survey. While the majority of OGLE's $\sim\!2000$ microlensing events are…

Astrophysics of Galaxies · Physics 2025-12-09 Bichu Li , Chan-Yu Tang , Zhuo-Ran Huang , Lei-Hua Liu

Detecting compact objects by means of their gravitational lensing effect on an observed companion in a binary system has already been suggested almost four decades ago. However, these predictions were made even before the first observations…

Solar and Stellar Astrophysics · Physics 2015-05-19 S. Rahvar , A. Mehrabi , M. Dominik

By monitoring $10^6$ quasars one could search for lensing by stars and Massive Compact Halo Objects (Machos) out to redshifts $z\sim 4$. If Machos have a present cosmological density $\Omega_{L,0}=1\%$, then the expected event rate is…

Astrophysics · Physics 2009-10-28 Andrew Gould

Since the first microlensing planet discovery in 2003, more than 200 planets have been detected with gravitational microlensing, in addition to several free-floating planet and black hole candidates. In this chapter the microlensing theory…

Earth and Planetary Astrophysics · Physics 2024-07-10 Natalia E. Rektsini , Virginie Batista

The detection of microlensing events from stars in the Large Magellanic Cloud and in the Galactic bulge raise important constraints on the distribution of dark matter and on galactic structure, although some events may be due to a new type…

Astrophysics · Physics 2020-11-25 David Valls-Gabaud

The strongly lensed gravitational wave (SLGW) is a promising transient phenomenon. However, the long-wave nature of gravitational waves poses a significant challenge in identification of its host galaxy. To tackle this challenge, we propose…

Instrumentation and Methods for Astrophysics · Physics 2025-05-08 Xikai Shan , Bin Hu , Xuechun Chen , Rong-Gen Cai

After decades of searching, the true nature of dark matter still eludes us. One potential probe of the form of dark matter in galaxy clusters is to search for microlensing variability in the giant arcs and arclets. In this paper, a simple…

Astrophysics · Physics 2007-05-23 Artem Tuntsov , Geraint Lewis , Rodrigo Ibata , Jean-Paul Kneib

The historical microlensing surveys MACHO, EROS, MOA and OGLE (hereafter summarized in the MEMO acronym) have searched for microlensing toward the LMC for a total duration of 27 years. We have studied the potential of joining all databases…

Instrumentation and Methods for Astrophysics · Physics 2018-09-10 Marc Moniez , Arash Mirhosseini

Microlensing consists in two major effects: (1) variation in the apparent position of the background sources (astrometric component) and (2) flux variations of the background sources (photometric component). While the latter has been…

Astrophysics · Physics 2009-09-25 S. Dib , J. Surdej , J. -F. Claeskens